Recent Advances in the Management of Anal Cancer

The Expression of HPV-16 E5 Oncoprotein Impacts the Transcript Profiles of FGFR2 and EMT-Related Genes in Preneoplastic Anal Epithelium Lesions

Anal Squamous Cell Carcinoma (SCCA) is a rare Human Papillomavirus type 16 (HPV16)-associated carcinoma whose pathogenesis is still poorly understood. Recent studies based on biopsy and Next Generation Sequencing (NGS) approaches have linked the viral episomal status to aggressive SCCA phenotypes, suggesting a potential role of the 16E5 oncoprotein in tumor development. Our previous findings indicated that 16E5 induces Fibroblast Growth Factor Receptor 2 (FGFR2) isoform switching, aberrant mesenchymal FGFR2c expression, Epithelial Mesenchymal Transition (EMT), and cell invasion in various in vitro human keratinocyte models, as well as in the in vivo context of cervical Low-grade Squamous Intraepithelial Lesions (LSILs). To further explore the role of 16E5 in epithelial carcinogenesis, this study aims to investigate the molecular profile in HPV-related anal lesions. The results showed a significant positive correlation between 16E5 and FGFR2c, as well as 16E5 or FGFR2c and key EMT-related transcription factors, particularly in the group of HPV16 positive anal samples not containing without high grade lesions. Additionally, by coupling the molecular analysis with an interactome investigation, we hypothesized a potential functional interplay between the Ca2+ channel Transient Receptor Potential Ankyrin 1 (TRPA1) and FGFR2c, mediated by 16E5 during the establishment of the oncogenic signaling. These findings will help to elucidate the actual relevance of 16E5 in the early progression of anal lesions and contribute to determine its potential as target for future preventive approaches for HPV16-positive SCCA.

Anal carcinoma - exploring the epidemiology, risk factors, pathophysiology, diagnosis, and treatment

Anal carcinoma is a relatively rare tumor that accounts for approximately 2% of gastrointestinal malignancies and less than 7% of anorectal cancers. Most anal tumors originate between the anorectal junction and the anal verge. Risk factors for the disease include human papillomavirus infection, human immunodeficiency virus, tobacco use, immunosuppression, female sex, and older age. The pathogenesis of anal carcinoma is believed to be linked to human papillomavirus-related inflammation, leading to dysplasia and progression to cancer. Squamous cell carcinoma is the most common type of anal tumor, with an annual incidence of approximately 1 to 2 per 100000 persons. Treatment regarding anal cancer has emerged over time. However, chemoradiation therapy remains the mainstay approach for early localized disease. Patients with metastatic disease are treated with systemic therapy, and salvage surgery is reserved for disease recurrence following chemoradiation. This article aims to provide background information on the epidemiology, risk factors, pathology, diagnosis, and current trends in the management of anal cancer. Future directions are briefly discussed.

Factors Influencing Outcomes and Survival in Anal Cancer

BACKGROUND

We aim to ascertain prognostic factors in the current management of anal cancer within this study.

METHODS

We reviewed the management and outcomes of anal cancer cases over a seven-year period, inclusive (2016-2023). The primary objectives were to assess the demographic characteristics, clinical presentation, and outcomes of all anal cancer patients within our institution. Kaplan-Meier survival analysis was used to estimate survival differences between cohorts, with statistical significance determined using log-rank testing. Cox proportional hazards regression was utilised to identify prognostic factors. Cox regression hazard ratios were reported along with confidence intervals and p-values.

RESULTS

The median follow-up time for the study was 29.8 months. Seventy-five patients with anal cancer were included in this study, with 88% (66/75) being squamous cell carcinoma (SCC) and the majority having regional disease (82.7% (62/75)). The median age at diagnosis was 63.4 years (36-94). There was a female preponderance (57.3% (43/75)). In total, 84% (63/75) underwent definitive chemoradiation (dCRT), with 7/63 (11.1%) requiring a salvage abdomino-perineal resection (APR) for residual or recurrent disease. Adverse prognostic indicators include those with T4 disease hazard ratio = 3.81, (95% CI 1.13-12.83, * p = 0.04), poorly differentiated tumour disease HR = 3.37, (95% CI 1.13-10.02, * p = 0.04), having N2 nodal status HR = 5.03, (95% CI 1.11-22.8, * p = 0.04), and having metastatic disease at diagnosis HR = 5.8, (95% CI 1.28-26.42, * p = 0.02).

CONCLUSION

Presenting characteristics including stage, nodal, and differentiation status remain key prognostic indicators in those diagnosed with anal malignancy.